This invention relates to a maintenance port system that facilitates the testing and troubleshooting of any computer-controlled panel from any automatic test set without requiring the test set computer or application software.
An automatic test set built to exercise a system (for example, an aircraft radar system) or a system component usually has one or more automatic panels that interface to the test set computer across a well-defined computer bus. During test, the test set computer controls or monitors the unit under test by transferring parameters to and from the appropriate panels at the appropriate time as dictated by application software.
Hardware engineers are required to obtain a working knowledge of application software and test set hardware, in addition to panel hardware, in order to debug their automatic panels. This requirement produces inherent delays in the debug and repair of these panels throughout the entire life of the test set.
For newly designed automatic test sets, delivery dates are delayed because of improper marriage between virgin panel hardware and virgin application software. In many instances, the hardware engineer sits idly by while the software engineer searches for the "bug" in this program. Conversely, the software engineer is idle while the hardware engineer repairs his panel. This serial effort --or "handshake"--between software and hardware has a tendency to string out test time.
Repair of automatic panels is a nightmare for technicians and follow engineers. Generally, a panel failure not readily detectable by the test set technician or follow engineer dictates that he either consult a resident expert on the panel, or become familiar with both the test set hardware and application software. Resident "experts", however, are quite forgetful and test set hardware/software familiarization can take several weeks.
The previous solution has been to check out any automatic panel on the test set using self test routines that, when executed would send test parameters to the panel and read back results. More sophisticated self test routines invoking a debugger for the modification of panel parameters might also have been provided. In either case, the following problems exist with this solution:
1. These routines must still be debugged and married to the panel. Unfortunately the application software normally takes precedence over self-test, and many times these routines are watered down in order that schedule be met.
2. The serial effort discussed earlier still exists.
3. Engineers must wade through the test set's software directory to find the names of the programs applicable to the self test on his panel.
4. Since self test routines vary in complexity and style from test set to test set, engineers are required to learn a different set of procedures for modifying similar types of parameters.
5. Test set malfunctions stagnate the repair cycle of the panel. The panel still requires the test set for all aspects of debug and repair.
U.S. patents of interest include U.S. Pat. No. 4,108,358 to Niemaszyk et al, which discloses a first unit which is a PROM dedicated for executive control functions and a second unit which is a RAM used as a scratch pad memory during test. Unit-under-test information is stored in external PROM cards. The combination of the executive test program and a PROM card automatically applies test paterns to the unit under test. Patents of general interest include U.S. Pat. Nos. 4,097,797 to Finet; 3,854,125 to Ehling et al; and 4,168,527 to Winkler; which disclose circuit testers adapted for testing standard electronic modules.